New/Modified Header Design?

[Solex68]

Anyone know what happened to the 4-2-1 stainless header that Garm bought years ago? Would be nice to get a couple pictures of that one up too.
1 3/8" - 1 1/2" - 2" iirc.

The guy who had Garm's car last didn't like that header. He said it made the Solexes too hot. He would trade those headers for a stock at the time.
I loved how they looked but I never got a good photo of them even though I tried.

[Daryl Smith]

From the pictures Garm posted I remember that they hung down below what they should have by a couple inches. That would need to be cut back/shortened.
If he has a good heat shield on and is experiencing excess heat I would suspect he is running too lean and or timing needs adjusting....Exhaust should be 1 3/4" with good flow through components...
A good header, one that improves power, WILL require carb adjustments, and possibly timing, to account for more airflow/better filling of the cylinders.
Even tho they are stainless, which is supposed to 'contain' the heat better than regular steel, a good ceramic coating and a proper heat shield would definitely improve things.
I do believe that header is a good design, I would spend the money getting it shortened to the proper height and ceramic coat it.

[Daryl Smith]

Just came accross this:
https://www.exhaustshop.com.au/products ... 273stm-547


Anyone try a test fit in a roadster?

[Solex68]

Just came accross this:
https://www.exhaustshop.com.au/products ... 273stm-547

Anyone try a test fit in a roadster?

Hmmm. Says "Image might not reflect actual exhaust system." I wonder if does look as pictured. If so, I think I would pick one up.

[Daryl Smith]

Came across some pictures of the Stainless 4-2-1 header I had built for the 1800.....1 3/8"-1 1/2"-2"
By the #'s this should be good for 130 - 140 hp, so, would be a good candidate for an R20 as well....should really boost the low rpm torque.

[Daryl Smith]

Some more....It looks good, but I was unhappy with some of the welding and decided not to accept it. Garm bought it for his car, and where it is now is anyone's guess...

[Alvin]

R16/stroker extractors from Lou:

[Daryl Smith]

How about some #'s there Alvin? Primary, secondary, and collector diameters?
Looks good, but, were'nt these made for the 2.3 L stroker @ about 190 hp?
Way overkill for the 1800 and 2000cc strokers @ 100 - 140 hp where most will end up.

[Daryl Smith]

Some very interesting reading in this thread....might have to consider downsizing my current header.....

10 pages long and you have to sign in to read it.
https://www.speed-talk.com/forum/viewto ... 15&t=55767

hoffman900 wrote:
"Calvin built a system for a friend of mine and is pushing over 75hp/cyl through 1 3/8" od tubing for the first 10" off the head (4cyl). So more peak than your BDA and I bet the power curve was muuucch smoother. The engine also needed two sizes less jet (Weber) with Calvin's system as the depression across the jet was greater. "

[Daryl Smith]

Junkyard trip yesterday with my brother looking for some parts and came across a 2002 Honda Civic with a 1.7L engine with the header exposed....

Honda 1.7L Header (Small).jpg

It is a short primary 4-1 header with approx. 1.25" OD pipes. The base 1.7L engine in the Civic is rated at 115 HP and 110 ft/lbs of torque.
Considering the different rating systems, that's easily 25 - 30 hp and 20 - 25 ft/lbs more than the stock R16 with a MUCH smaller header.
If a smaller, properly sized header were available for the R16, you would likley see a performance improvement when installed, and I wouldn't have to listen to this crap about the stock exhaust manifold being so good (it isn't, it just does the job, much like the 1 1/2" available header).

[23yrRebuild]

Hey Daryl,
That's interesting...I'd be curious to know the valves & cam specs that go with the 1.7 L , to make those numbers using that small diameter header.
Mike

[Alvin]

From Shiro Osumi in the Fairlady Facebook group. $2650 for full system, $1480 for header only:

[spl310]

Note that it is a stainless header and exhaust.

[Gregs672000]

Daryl, did you ever have another header made? The first looked nice.

[JT68]

Since we build SS exhausts, we have obviously thought about SS headers..I’m sure Lou’s “extractor” would improve power output, but the collector design on the Japanese version likely eliminates any benefits from the fancy primaries on that one. It’s cute, but seriously doubt there is any meaningful power increase over a TriMill. We know from previous posts that 1 5/8 primaries do basically nothing useful under 7500 rpm, which agrees with Daryl’s thinking as well. Just like the TriMill and recent copies of the TriMill, the collector is way to short to be ideal. I think that’s simply the trade off we accept for easy install.


A more basic question for the group, is there really a market for a 1500$ stainless header in the US? Feel free to pm.

Reality check though, on a basic roadster engine your talking single digit hp increases if all the stars align.